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1.
《中国有色金属学会会刊》2021,31(11):3530-3548
In-situ LA-ICP-MS and S isotopes of pyrite from the Baoshan Cu polymetallic deposit were conducted to investigate the ore-forming process and the enrichment mechanism of elements. Three generations of pyrite (Py I, Py II, and Py III) in the skarn-type ores and pyrite in the carbonate-hosted sulfide ores from central, western, and northern (C_Py, W_Py, and N_Py) mining districts are selected for comparison. Compared with Py I and Py III, the contents of most elements in Py II are apparently higher. The As and Se contents are high within a wide range and are decoupled in the growth band of the C_Py. The highest As, Se, and Pb contents were found in W_Py and N_Py. These results indicate the drastic changes in the temperature and fluid mixing during the mineralization. The occurrence of fluctuation and change in temperature and f(O2) was triggered by intermittent pulses of magmatic-hydrothermal fluids, mixing with meteoric water, and water−rock interactions. The sulfur isotopes of all species of pyrite indicated the magmatic source. The change in the f(O2) conditions caused slight differences in the sulfur isotope compositions. Consequently, a metallogenic model was proposed to explain the ore-forming processes. 相似文献
2.
Oguzhan Oguz Nicolas Candau Adrien Demongeot Mehmet Kerem Citak Fatma Nalan Cetin Grégory Stoclet Véronique Michaud Yusuf Z. Menceloglu 《Polymer Engineering and Science》2021,61(4):1028-1040
There is currently considerable interest in developing stiff, strong, tough, and heat resistant poly(lactide) (PLA) based materials with improved melt elasticity in response to the increasing demand for sustainable plastics. However, simultaneous optimization of stiffness, strength, and toughness is a challenge for any material, and commercial PLA is well-known to be inherently brittle and temperature-sensitive and to show poor melt elasticity. In this study, we report that high-shear mixing with cellulose nanocrystals (CNC) leads to significant improvements in the toughness, heat resistance, and melt elasticity of PLA while further enhancing its already outstanding room temperature stiffness and strength. This is evidenced by (i) one-fold increase in the elastic modulus (6.48 GPa), (ii) 43% increase in the tensile strength (87.1 MPa), (iii) one-fold increase in the strain at break (∼6%), (iv) two-fold increase in the impact strength (44.2 kJ/m2), (v) 113-fold increase in the storage modulus at 90°C (787.8 MPa), and (vi) 103-fold increase in the melt elasticity at 190°C and 1 rad/s (∼105 Pa) via the addition of 30 wt% CNC. It is hence possible to produce industrially viable, stiff, strong, tough, and heat resistant green materials with improved melt elasticity through high-shear mixing. 相似文献
3.
For proton-exchange membrane fuel cells, the distribution of reactant flow in the stack is critical to the fuel cell's efficiency. The uneven distribution of reactant flow in the stack may cause poor current density, low performance, and material degradation. To understand and accurately predict the flow field in the proton-exchange membrane fuel cell system, the present study aims to develop a simple correlation to analyze the pressure drop in fuel cell stacks. The flow channel in each cell of a stack is treated as a porous medium, and a power-law model is used to approximate the porous medium momentum source term. For the stacks with fewer cell numbers, namely, 1, 5, and 10 cells, the parameters in the power law are established based on the experimental data. Then, a correlation is developed to simulate the flow and predict the pressure drop in the stack with higher cell numbers (ie, 20 and 40 cells). The simulations show that the pressure drop in each cell of a stack is almost invariable, and the average pressure drop decreases with increasing the number of cells. The flow uniformity in the stacks with different cell numbers is evaluated using the dimensionless pressure drop and the pressure drop ratios. It suggests that the lower the cell number, the more uniform the pressure drop. The developed model is conducive to efficiently designing the flow channel for a fuel cell stack with large cell numbers. 相似文献
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5.
Margarida S. C. A. Brito Joana Matos Marina V. L. Torres Claudio P. Fonte Madalena M. Dias José Carlos B. Lopes Ricardo J. Santos 《American Institute of Chemical Engineers》2022,68(4):e17597
Product formulations for industrial processes are typically developed at laboratory scale. However, the mixing conditions are not easily mimicked in the laboratory. A rotational device is proposed in this study as a fast laboratory-scale formulation development, which enables mimicking the mixing conditions in the industrial process. The geometrical configurations of the rotational device are from rheometry devices (plate-plate and cone-plate). The main advantages of this method are the small amounts of raw materials and shorter testing times. This methodology is applied to an industrial case study, the reaction injection molding (RIM) process. The mixing length scales evolution in the rotational rheometer were matched to those in RIM machines. The main novelty of this study is the introduction of a protocol that bridges the processing conditions at laboratory using small amounts of raw materials to high throughput continuous flow reactors. 相似文献
6.
采用干法和湿法两种混炼工艺制备了螺旋纳米碳纤维(HCNFs)/炭黑(CB)/天然橡胶(NR)复合材料,通过扫描电镜、拉伸试验机和应变扫描仪分别对所制备复合材料的界面形貌、力学性能和Payne效应进行了测试分析,考察了混炼方式对复合材料宏观力学性能及Payne效应的影响。结果表明,与纯CB填料相比,在干湿两种混炼方式下,添加适量的HCNFs(1~6份)能提高HCNFs/CB/NR复合材料的300%定伸应力、扯断伸长率、拉伸强度和硬度。与干法混炼相比,湿法混炼能明显增强HCNFs/CB/NR复合材料的Payne效应,并提升在HCNFs高添加量(2~6份)条件下的拉伸强度和扯断伸长率,这主要源于湿法混炼能够有效改善HCNFs在橡胶基质中的分散性。 相似文献
7.
在处理多晶硅生产中产生的残液时,残液搅拌罐填料密封出现泄漏,针对此问题提出了优化措施,达到了预期效果。 相似文献
8.
为给纺织行业在纺织品贸易和质量控制等方面优选色差公式提供参考,研究了3个重要的和1个最新色差公式的色差均匀性,借助国际上色样多、视觉等距性好的汉风色典,利用X-Rite测色仪测试近2万个色样的色度参数,然后分别从向度、彩度、浓度3个方向选取3万多对相邻色样,采用MatLab编程计算4种色差并统计分析其均值、不匀率和性能因子。结果表明:不同方向不同评价指标所得结果不尽相同;在色差均匀性方面,CAM16-UCS最好,CIEDE2000(2∶1∶1)略优于CMC(2∶1),且二者明显优于CIELAB;在色差大小方面由小到大依次为CIEDE2000(2∶1∶1)、CMC(2∶1)、CAM16-UCS、CIELAB。 相似文献
9.
D-最优混料设计优化树莓平菇解酒片主料配比 总被引:1,自引:0,他引:1
红树莓中富含的鞣花酸和其聚合物以及其他化合物具有解酒功能,该文利用所培育出的树莓平菇,添加传统药膳葛花、拐枣、苦荞以及具有养胃功效的小米进行平菇解酒片的开发。采用软件Design Expert(V.8.0.6)中的混料(mixture)设计D-Optional的方法,以体外乙醇脱氢酶(alcohol dehydrogenase,ADH)的激活率为评价指标,设计解酒片的最佳主料配方。通过建立各组分不同比例与ADH激活率之间的回归模型,考察该配方中各组分的交互作用对响应值的影响,利用软件的优化功能和验证试验得出最佳主料配方为:小米粉31.2%、苦荞粉21.7%、平菇粉20.5%、葛花粉16.8%、拐枣粉9.8%,在该条件下对ADH的激活率最大达到15.87%,验证试验结果与预测值相吻合,表明采用本方法优化得到的处方工艺稳定可靠。 相似文献
10.